1. Field of the Invention
The present invention relates to a light source unit and a projector which incorporates the light source unit.
2. Description of the Related Art
In these days, projectors are used in many cases as an image projection apparatus for projecting screens and video images of a personal computer and, further, images based on image data stored in a memory card on to a screen. In projectors of this type, light emitted from a light source is concentrated on to a micromirror display device referred to as a DMD (Digital Micromirror Device) or a liquid crystal panel so as to display a color image on to the screen.
In these projectors, conventionally, projectors employing highly bright discharge lamps as light sources have been the mainstream of projectors. In recent years, however, there have been developments in projectors employing, as light sources, red, green and blue light emitting diodes or solid-state light emitting devices such as an organic electroluminescence display, and there have been made many proposals. For example, Japanese Unexamined Patent Publication No. 2004-341105 proposes a light source unit which is made up of a phosphor layer for converting ultraviolet light emitted from a solid-state light source into visible light, a transparent base material and the solid-state light source.
However, since the proposed light source unit by Japanese Unexamined Patent Publication No. 2004-341105 employs the excitation light source which uses ultraviolet light with high energy as excitation light, the optical component on to which ultraviolet light is shone is liable to be damaged, leading to a problem that ensuring a long life for the optical component becomes difficult.
The problem that the invention is to solve is to provide a light source unit which can maintain its performance over a long period of time by suppressing the deterioration with age of an optical component on to which excitation light is shone and a projector including the light source unit.